Sex Classes Research Articles

A multidisciplinary pulmonary embolism response team (PERT): first experience from a single center in Germany.

Over the last few years, the concept of multidisciplinary pulmonary embolism response teams (PERTs) has emerged to encounter the increasing variety and complexity in managing acute pulmonary embolism (PE). To investigate PERT's composition and added clinical value in a university center in Germany. Over 4years (01/2019-11/2022), patients with confirmed PE were enrolled in a prospective single-center cohort study (PERT Mainz). We investigated the composition of PERT and compared, after propensity score matching, patients with acute PE before and after the initiation of PERT at our Medical University Centre. The primary outcome was in-hospital PE-related mortality. From 2019 to 2022, 88 patients with acute PE with a PERT decision were registered. Of those, 13 (14.8%) patients died during the in-hospital stay. Patients evaluated by a PERT had a median age of 68; 48.9% were females, and 21.7% suffered from malignancy. Right ventricular dysfunction was present in 76.1% of all patients. In total, 42.0% were classified as intermediate-high-risk PE and 11.4% as high-risk PE. First PERT contact mainly originated from emergency departments (33.3%) and intensive care units (30.0%), followed by chest pain units (21.3%) and regular wards (12.0%). The participation rate of medical specialties demonstrated that cardiologists (100%) or cardiac/vascular surgeons (98.6%) were included in almost all PERT consultations, followed by radiologists (95.9%) and anesthesiologists (87.8%). Compared to the PERT era, more patients in the pre-PERT era were classified as simplified pulmonary embolism severity index (sPESI) ≥ 1 (78.4% vs 71.6%) and as high-risk PE according to ESC 2019 guidelines (18.2% vs. 11.4%). In the pre-PERT era, low- and intermediate-low patients with PE received more frequently advanced reperfusion therapies such as systemic thrombolysis or surgical embolectomy compared to the PERT era (10.7% vs. 2.5%). Patients in the pre-PERT were found to have a considerably higher all-cause mortality and PE-related mortality rate (31.8% vs. 14.8%) compared to patients in the PERT era (22.7% vs. 13.6%). After propensity matching (1:1) by including parameters as age, sex, sPESI, and ESC risk classes, univariate regression analyses demonstrated that the PE management based on a PERT decision was associated with lower risk of all-cause mortality (OR, 0.37 [95%CI 0.18-0.77]; p = 0.009). For PE-related mortality, a tendency for reduction was observed (OR, 0.54 [95%CI 0.24-1.18]; p = 0.121). PERT implementation was associated with a lower risk of all-cause mortality rate in patients with acute PE. Large prospective studies are needed further to explore the impact of PERTs on clinical outcomes.

Indirect methods for predicting the body composition of sheep of different sex classes

The aim was to evaluate the correlation and develop regression equations for the body composition of sheep of different sex classes, obtained by the comparative slaughter method, using the composition of the neck region and loin eye area (LEA). Forty-five sheep of three sex classes (15 intact males, 15 castrated males and 15 females) received three feeding levels (ad libitum or restrictions of 70 or 80% of ad libitum intake). Animals were distributed in a 3×3 factorial arrangement, with 5 repetitions. The LEA showed: positive correlation with empty body weight, fasting body weight, meat, protein, ether extract and water (p < 0.01), for all sex classes; with bones for intact males and females (p < 0.01); with ash content for intact males and a moderate correlation for castrated males (p < 0.01). The neck was correlated with empty body weight, fasting body weight, meat, protein, ether extract, water and energy in all sex classes (p < 0.01); and moderate correlation with bone (r=0.58) and ash (r=0.67) for intact males. Intact males showed higher R² values in their prediction equations in relation to the other sex classes.

Berganês, a new sheep breed from the Brazilian semiarid: performance and carcass traits in different sex-classes by univariate and multivariate approaches

Twenty-four lambs between four and five months of age were divided into sex classes: uncastrated males, castrated males and females, eight for each treatment, with an average body weight of 27.00 ± 3.13 kg. dry matter and water intakes were higher for uncastrated males (p < 0.001). final body weight, body weight at slaughter, average daily gain and cold carcass weight were greater for uncastrated, intermediate for castrated and lower for females (p < 0.05). hot and cold carcass yields were higher for castrated males and females, respectively. (p < 0.05). based on principal component analysis, twenty-five variables were selected out of thirty-two, in some of the seven principal components generated, summarizing 21.87% data dimension. Discriminant analysis identified greater discrimination power for body weight at slaughter, thorax width, thorax depth, fatness, dry matter intake and hot carcass weight. All lambs were classified into their respective sex classes. Therefore, uncastrated males have performed better than castrated ones and both showed higher performance than females. Females and castrated males showed higher carcass yield. Discriminant analysis indicated heterogeneity between sex classes.

Is Food Addiction a Specific Feature of Individuals Seeking Dietary Treatment from Nutritionists?

Food addiction (FA) is a condition characterized by excessive and dysregulated consumption of high-energy food, and impulsivity. The diagnostic and nosological framework of FA is still controversial. Therefore, this study aimed at exploring the prevalence of FA in patients seeking help from nutritionists for weight loss, along with its relationship with eating habits, in a pool of 842 participants of both sexes. Eating habits and FA were assessed by, respectively, a self-administered questionnaire and the Yale Food Addiction Scale (YFAS). Statistical analysis included Chi-square for categorical variables, independent t tests to investigate continuous variables and an univariate logistic regression analysis to determine potential risk factors for FA. The relationship between FA diagnosis and potential risk factors was assessed through a stepwise logistic regression model, controlling for age, sex, and body mass index (BMI) classes. Our results indicate that a prevalence of FA in our sample was 15.3%, with no difference between women and men. A higher prevalence was recorded in overweight subjects or obese. According to the YFAS criteria, women were more likely to report a persistent desire and withdrawal than men. Patients with FA compared with those without it, reported a greater number of attempts to lose weight, to self-dieting, a different mealtime repertoire, and to nibble continuously throughout the day. Moreover, the amount of carbohydrates ingested in the same meal seems to represent an eating habit significantly associated with FA. Taken together, our findings show how patients seeking help from nutritionists may display some peculiar features of FA. In spite of its diagnostic controversies, it is evident that FA may play a role in obesity and may also be a feature of some psychopathological conditions. Therefore, it should be more deeply investigated and possibly specifically targeted with tailored therapeutic interventions.

PSXII-15 Automatic Estimation of Body Condition Score in Finished Cattle Using Deep Learning Computational Architectures in Two-Dimensional Images

Abstract The objective of this research was to investigate the possibility of using computational architectures of deep learning neural networks (deep learning) in two-dimensional images to automatically estimate the BCS (body condition score) in beef cattle. Data collection lasted from March 2021 to December 2022 and was carried out on a commercial farm in Mato Grosso do Sul, Brazil. Data from 1,570 animals of different genetic compositions, sex classes, ages and body weights were used. The animals were randomly selected in the confinement stalls, identified and concomitantly. To obtain the RGB digital images, the 3DBeef @Tech device was used, which was implemented in Python (based on OpenCV, 2015). The sensor was positioned in the passageway at a distance of 2.50 meters, allo wing the collection of images of only one animal at a time. The bBCS was evaluated remotely by trained professionals during the data collection period, ranging from 1 to 9, through the visualization of fat deposition and muscle coverage in certain anatomical points of the animal. The collected images and evaluations were used as input for a segmentation convolutional neural network (CNN; Figure 1). The labeled data set was divided into training, validation and testing, respectively in the proportions of 65%, 25% and 10%. A deep neural network was constructed to classify BCS using Python and the deep learning library Tensorflow and run through a Pro+ instance of Google Collaboratory. The results obtained show that, despite the small amount of data currently available for training, the neural network had a performance designed to classify BCS, with training accuracy of 80.5% and validation accuracy of 65.9% (Figure 2 and 3). when compared with professional raters. The validation still exhibited accuracy, recall, F1-score and AUC of 0.6676, 0.6562, 0.6562 and 0.9519 (P < 0.05), respectively. Despite the fact that the BCS assessment is a problem of difficult visual classification, both due to the variability of possible scenarios and the subtle difference between different BCS scores. It is believed that with a greater number of evaluated images, an accuracy greater than 90% will be achieved for the BCS. Therefore, it is necessary to continue with studies to obtain a greater number of images collected in search of greater accuracy.

The benthic-pelagic continuum: Age class and sex differences in the use of the vertical dimension by a rare pinniped.

Sea lions as a group, display strong site fidelity, and varying degrees of vulnerability to environmental change, disease and fisheries interactions. One of the rarest pinnipeds, the New Zealand sea lion (NZSL, Phocarctos hookeri) has a very restricted breeding range. At Campbell Island/Motu Ihupuku, one of the two primary breeding sites, at-sea foraging behaviour is unknown. We hypothesised that NZSL of various sex and age classes would utilise the water column differently due to differing physiological constraints and therefore have different accessibility to prey resources. We tested whether sea lion diving behaviour varied in relation to (i) age and sex class, (ii) time of day and (iii) water depth. We also hypothesised that the proportion of benthic/pelagic diving, and consequently risk of fisheries interaction, would vary in relation to age and sex. Satellite telemetry tags were deployed on 25 NZSL from a range of age/sex classes recording dive depth, duration and location. Adult females and juveniles used inshore, benthic habitats, while sub-adult males also utilised benthic habitats, they predominantly used pelagic habitat at greater distances from the island. Adult females and juveniles exhibited shorter dives than the same age/sex classes at the Auckland Islands, suggesting a lower dive effort for these age/sex classes at Campbell Island/Motu Ihupuku. Adult females dived more frequently than other age/sex classes, likely operating closer to their physiological limits; however, further data for this age class is needed. Sub-adult male use of pelagic prey may increase their exposure to mid-water trawls; however, further research detailing the degree of spatial overlap with fisheries is required. This study highlights the utility of spatially explicit dive data to predict vertical habitat use, niche separation of various age and sex classes of marine predators and attribute potential fisheries interaction risk in relation to predator habitat use.

Foraging segregation by sex and age class in the Guadalupe fur seal from Guadalupe Island, Mexico

AbstractA proper assessment of the foraging habits of the Guadalupe fur seal (GFS; Arctocephalus townsendi) is a priority to better understand its recovery, in which the potential for intraspecific competition for prey and space resources is expected to lead to segregation. This study aimed to determine the foraging habits of different sex and age classes. A total of 146 GFS fur samples was collected at Guadalupe Island, Mexico (2014–2020) for stable isotopes (δ13C and δ15N) analysis. Isotopic areas were created (SIBER package in R). Significant isotopic differences were observed between classes. Male (3.6‰2) and female (3.0‰2) juveniles had the largest isotopic areas due to a greater foraging dispersion. Adult females showed the lowest mean δ15N value (16.1‰ ± 0.5‰) due to foraging trips that are mostly performed towards high latitudes. Except for pups, adult and subadult males presented the highest mean δ15N (17.4‰ ± 0.4‰) and δ13C values (−17.0‰ ± 0.8‰) due to a possible higher trophic level and coastal foraging habits, whereas pups presented the highest mean δ15N value (17.6‰ ± 0.3‰) because of lactation, which reflects their mothers δ15N signal plus their own enrichment. Our findings suggest a segregation explained by differences in life history, energy requirements, and a possible strategy to avoid competition.

Survival strategy–Temporal segregation of different age and sex classes of a Bengal tiger (Panthera tigris tigris Linnaeus) population in Pench Tiger Reserve, Madhya Pradesh India

Survival strategy–Temporal segregation of different age and sex classes of a Bengal tiger (Panthera tigris tigris Linnaeus) population in Pench Tiger Reserve, Madhya Pradesh India

Population demography of the Blackbuck Antilope cervicapra (Cetartiodactyla: Bovidae) at Point Calimere Wildlife Sanctuary, India

Demographic research utilizing vital rates and life tables is a standard aspect of planning protection and management strategies for wildlife populations. The Blackbuck Antilope cervicapra population at Point Calimere Wildlife Sanctuary, Tamil Nadu, has undergone fluctuations in recent decades. The cause remains elusive, and conservation efforts may be hampered by a lack of population data. This study aimed to estimate demographic parameters using population count and age-sex classification data collected for the years 2017─2020. The overall mean population estimate derived from line-transect distance sampling was 719, with annual estimates of 716, 727, 711, and 722 for the years 2017–2020 respectively. In total, 64% of Blackbucks counted were adults, 19% subadults, and 17% fawns. Mortality was highest for adult and subadult classes for the composite female class, and fawn mortality was 20%. The net reproductive rate (R0) was as low as 3.28 offspring per generation contrasted with a rather longer mean generation time (G) as 4.75 years. Thus, the study observes a decrease in Blackbuck numbers postulated in earlier research to be driven principally by a conglomerate of factors, including reduction of usable space and interspecific resource competition. Our findings provide a baseline demography of the species and highlights the value of long-term demographic monitoring of age sex classes to understand the evolution of life histories.

Spatial and temporal harvest risk to polar bears in the Canadian Beaufort Sea

Subsistence harvest in Arctic marine ecosystems is influenced by sea ice conditions affecting species distributions, abundance, and accessibility. We tracked 78 polar bears ( Ursus maritimus Phipps, 1774) of different age, sex, and reproductive classes via satellite telemetry in the Canadian Beaufort Sea (2007–2014, n = 71 258). We assessed vulnerability to harvest (no/low/medium/high) based on telemetry data overlap with density of historical harvest locations (1985–1987, n = 121). All classes of polar bears were detected in historical harvest areas of low to high risk in greater proportion than expected from available area during the harvest period (January to ice breakup), and all but solitary adult females had >50% of locations in the risk areas. Subadult males were proportionally more often inside risk areas yet were not observed in the high-risk areas. Other classes were observed <1% of the time in high-risk areas yet still proportionally greater than expected from available area. Landfast ice has declined in the pre-melt (January–March) and end-of-harvest (June–July) seasons (1980–2021), with the rate of decline being greater in lower-risk areas ( p ≤ 0.05). With sea ice predicted to decline in the future, we suggest that polar bears in the Beaufort Sea may become more concentrated into areas of higher harvest risk.

Self-reported symptoms after COVID-19 vaccination. Distinct sex, age, and geographical outcomes in Lebanese and Italian cohorts

Following the COVID-19 discovery in December 2019, different vaccines were authorized in 2021 in Italy and Lebanon, but side effects and the impact of sex and age remained partly explored. We designed a web-based “Google Form” questionnaire to record self-reported systemic and local side effects up to 7 days after 1st and 2nd dose of the vaccine in two distinct Italian and Lebanese cohorts. Twenty-one questions in Italian and Arabic languages explored the prevalence and severity of 13 symptoms. Results were compared with respect to living country, timing, sex, and age classes. A total of 1,975 Italian subjects (age 42.9 ± SD16.8 years; 64.5% females) and 822 Lebanese subjects (age 32.5 ± SD15.9 years; 48.8% females) joined the study. The most common symptoms in both groups were injection site pain, weakness, and headache after the 1st and 2nd doses. The rate of post-vaccinal symptoms and the severity score were significantly higher in females than in males and progressively decreased with increasing age following both doses. We find that among two populations from the Mediterranean basin, the anti-COVID-19 vaccine generates mild age and sex-dependent adverse effects, with ethnic differences and prevalent symptoms rate and severity in females.

Population size and residency patterns of northern bottlenose whales (Hyperoodon ampullatus) using the Gully, Nova Scotia

A population of northern bottlenose whales (Hyperoodon ampullatus) uses the Gully, a submarine canyon off the coast of Nova Scotia, Canada. Eleven years of photo-identification records has permitted estimation of population size using mark-recapture techniques. The population estimate was small (133 individuals, 95% CI = 111-166 from left side identifications; 127 individuals, 95% CI = 106-160 from right side identifications). The population was not closed, with the combined mortality, mark change and emigration rate estimated at 13% per year for left side identifications (95% CI = 9-17) and 14% for right side identifications (95% CI = 10-18). There was no significant increase or decrease in the population size between 1988-1999 (change in population size: left side: –0.13% per year, 95% CI = -3.4 to 3.9; right side: –0.43% per year, 95% CI = -4.5 to 3.1). The sex ratio was roughly 1:1, with equal numbers of sub-adult and mature males. Over the summer field season, individuals emigrated from, and re-immigrated into the Gully, spending an average of 20 days within the Gully before leaving (left side identifications 19 days, SE = 17; right side identifications 23 days, SE = 10). Approximately 34% of the population was present in the Gully at any time. Individuals of all age and sex classes displayed similar residency patterns although there were annual differences as individuals spent less time in the Gully in 1996 than in 1990 and 1997. Sighting rates were similar in all years with extensive fieldwork, indicating little variability in the number of whales in the Gully each summer. Accurate estimates of population size and residency patterns will be useful in determining the regulations and required coverage for a marine protected area in the Gully.

Age differences in the responses of vervet monkeys, Chlorocebus pygerythrus, to terrestrial alarm calls

The high costs of predation and the opportunity costs associated with predator avoidance are likely to select for flexibility in the development of antipredator responses based on local socioecological conditions. As group size is hypothesized to vary across populations as a function of predation risk, the development of antipredator behaviours throughout ontogeny may be influenced by the size of an individual's social group. Here, we explore the development of alarm call responses in wild vervet monkeys living at the Samara Game Reserve, South Africa. Vervet monkeys at this site live in relatively large social groups, and adult responses to alarms have previously shown less uniformity than in other sites where group sizes are smaller. We presented monkeys playback recordings of terrestrial alarm calls produced by individuals of different age–sex classes. We then videorecorded and scored the responses of receivers along an ordinal maturity scale. We used a mixed-effects ordinal logistic regression model within a Bayesian framework to explore how response intensity is affected by the age–sex of the caller, and the age of receivers. Our analysis showed that younger monkeys (<2 years old) exhibit strong evasive responses to call stimuli, regardless of the age–sex class of the caller. The intensity of these responses decreases with age, with responses to nonalarm calls decreasing earlier in development than responses to alarm calls. Adult responses to alarm calls in this population are as likely to be characterized by a general increase in vigilance as they are to consist of an evasive response. We suggest that responses in younger individuals at Samara are mediated by generalized startle responses to loud, plosive noises. Development of more specific responses throughout ontogeny is likely to be dependent on learning from adult models, whose milder responses reflect local socioecological conditions specific to Samara.

A Quantitative Assessment of Trainers-Dolphins' Interactions in the Absence of Food Reward.

All the studies that have considered the motivation of the dolphins to interact with their trainers as a possible welfare indicator have been carried out in facilities where the trainer-dolphin interactions (TDIs) sessions were reinforced with food. Therefore, in these specific circumstances, it was difficult to separate the motivation of the dolphins interacting with the trainers from the food drive. The current study aims to assess the interaction between the trainers and the dolphins in the absence of food rewards. The research was carried out at The Dolphin Reef (Eilat, Israel), a facility where the interaction between the trainers and 14 bottlenose dolphins of different sex and age classes did not involve food rewards. A total of 531 TDIs were recorded, with dolphins participating in 94.5% of the sessions and an average of three dolphins per session. The dolphins participated in a higher number and more frequently in the TDIs when toys were provided by the trainers. Diel and seasonal differences were also observed, with the dolphins participating more during the morning sessions and the neutral season. The latency of response of the dolphins to the presence of the trainers on the platform or in the water, whether or not advertised by the trainers' signal ("call" or "no-call"), was very short (usually less than 1 min), and the dolphins often anticipated the beginning of the sessions by arriving at the trainers' location before or upon the caretakers' arrival (96% of the time). Individual differences in the participation in the TDIs were also recorded, which might be linked to both the dolphin's health/welfare status or their personality. The current study shows that the separation of the TDIs from the food reward allows for a better understanding of the willingness of dolphins under human care to interact with their trainers. In addition, the results presented in this paper show that such TDIs are an important part of these dolphins' lives, which suggests that these interactions might be an additional tool to improve the animals' social environment and monitor their welfare.

GTExVisualizer: a web platform for supporting ageing studies.

Studying ageing effects on molecules is an important new topic for life science. To perform such studies, the need for data, models, algorithms, and tools arises to elucidate molecular mechanisms. GTEx (standing for Genotype-Tissue Expression) portal is a web-based data source allowing to retrieve patients' transcriptomics data annotated with tissues, gender, and age information. It represents the more complete data sources for ageing effects studies. Nevertheless, it lacks functionalities to query data at the sex/age level, as well as tools for protein interaction studies, thereby limiting ageing studies. As a result, users need to download query results to proceed to further analysis, such as retrieving the expression of a given gene on different age (or sex) classes in many tissues. We present the GTExVisualizer, a platform to query and analyse GTEx data. This tool contains a web interface able to: (i) graphically represent and study query results; (ii) analyse genes using sex/age expression patterns, also integrated with network-based modules; and (iii) report results as plot-based representation as well as (gene) networks. Finally, it allows the user to obtain basic statistics which evidence differences in gene expression among sex/age groups. The GTExVisualizer novelty consists in providing a tool for studying ageing/sex-related effects on molecular processes. GTExVisualizer is available at: http://gtexvisualizer.herokuapp.com. The source code and data are available at: https://github.com/UgoLomoio/gtex_visualizer.

Multidisciplinary Pulmonary Embolism Response Team (PERT) a propensity score matched single centre experience from Germany

Abstract Funding Acknowledgements Type of funding sources: None. Background Over the last years, the concept of multidisciplinary pulmonary embolism response teams (PERTs) has emerged to encounter the increasing variety and complexity in the management of acute pulmonary embolism (PE). Purpose To investigate the composition and added clinical value of PERT in our city. Methods Over a 5-year period (01/2017-09/2022), patients with confirmed PE were enrolled in a prospective single-centre cohort study (PERT). We investigated the composition of PERT and compared, after propensity score matching, patients with acute PE prior and after the formation of PERT at our institution. The primary outcome was in-hospital PE-related mortality before and after the formation of PERT. Results During the period from 2017 to 2022, 88 patients with acute PE with a PERT decision were registered. Of those, 13 (14.8%) patients died during the in-hospital stay. Patients evaluated by a PERT had a mean age of 68 years; among these 48.9% were females, and 21.7% suffered from malignancy. Right ventricular dysfunction was present in 84.9% of the patients. In total, 42.0% were classified as intermediate-risk PE and 11.6% as high-risk PE. First PERT contact originated mostly by emergency departments (33.3 %) and intensive care unit (30.0%), followed by chest pain unit (21.3%) and regular ward (12.0%) (Figure 1a). The participation rate of specialties demonstrated that cardiologists (100%) or cardiac/vascular surgeons (98.6%) were included in almost all PERT activations followed by radiologist (95.9%) or anesthesiologist (87.8%). Further disciplines were present in few cases as summarized in Figure 1b. When comparing patients characteristics of the pre-PERT era with the PERT era, more patients were classified as sPESI ≥1 and as high-risk according to ESC 2019 guidelines in the pre-PERT era (78.4% and 18.2%) opposed to the PERT era (71.6 and 11.4%) (Figure 2). A considerable higher all-cause mortality (31.8% vs. 14.8%) and PE-related mortality rate (22.7% vs. 13.6%) was observed in patients in the pre-PERT era compared to the PERT era. After propensity matching (1:1) by including parameters as age, sex, sPESI and ESC risk classes, an univariate regression analyses demonstrated, that the PE management based on a PERT-decision was associated with lower risk of all-cause mortality (OR, 0.37 [95%CI 0.18-0.77]; p=0.009) and PE-related mortality (OR, 0.54 [95%CI 0.24-1.18]; p=0.121) compared to patients without a PERT-decision. Conclusion PERT implementation tended to reduce the mortality rate in patients with acute PE. Large prospective studies are needed to further explore the impact of PERTs on clinical outcomes.

Obtaining Sustainable Population Structures for the Management of Red Deer

Cervus elaphus populations are spreading and growing in many parts of Europe. This growth can have detrimental effects on biodiversity and ecosystem function. Successful strategies to manage large herbivores require reliable information on density and population trends. This paper presents a methodology to achieve a sustainable distribution of red deer by age and sex classes over time. Instead of traditional algebraic methods, the method consists of a simple iterative process that uses convergence to obtain the dominant eigenvalue and eigenvector of the biological matrix from an initial population. This eigenvalue represents the annual growth rate of the population, and the eigenvector represents the ideal age and sex class distribution of the population. The method has been applied to a fenced preserve in the province of Toledo, Spain. An annual population growth rate of 1.63 (dominant eigenvalue of the biological matrix) was obtained from an initial population and the biological matrix of the deer on the preserve. The convergence of this rate occurred in year 14, but the carrying capacity allows for a population close to the population in year 17 according to the prediction, which is therefore considered to be the year when the ideal population distribution is achieved. This methodology allows managers to numerically justify how to control population growth to preserve biodiversity and sustainability.

A review of gray whales (Eschrichtius robustus) on their wintering grounds in Mexican waters

The Eastern North Pacific gray whale (Eschrichtius robustus) is one population of large cetacean that has recovered from depletion resulting from commercial harvest in the mid- to late-1800s. It is believed that this population may be approaching, or possibly exceeding its carrying capacity as suggested by recent increases in mortality of all age and sex classes. Research on the breeding biology and phenology of gray whales that spend the winter in the coastal waters and lagoons of Baja California, Mexico has been conducted for many years. These studies contribute valuable information on the reproductive biology of this species, and the importance of their coastal lagoon habitats to their reproductive success. This paper reviews and summarises historical exploitation, conservation measures, the findings of research conducted on gray whales in their winter breeding range, potential natural and anthropogenic threats to this population, and makes recommendations for future research and monitoring. This review concentrates on the findings of research conducted since the mid-1970s.

Ticks (Parasitiformes: Ixodida: Ixodidae) parasites of wild Baird’s tapirs (Mammalia: Perissodactyla) in the Yucatan Peninsula, Mexico

ABSTRACT Tapirs are common hosts of ticks and an individual can be infested by up to seven different tick species. We explored the parasitic tick fauna associated with wild Baird’s tapirs (Tapirus bairdii) from the Yucatan Peninsula. A total of 326 ticks of 10 species of the Family Ixodidae were collected from 15 tapirs. We found a range of one to six tick species per host, but most of the tapirs were parasitized by two or three tick species. We tested the relationship between body condition, sex, and age classes of the tapirs versus the number of tick species on each host. The most common tick species was Amblyomma mixtum found on 93% of the hosts. Amblyomma pecarium, Amblyomma tenellum, Ixodes affinis and Rhipicephalus sanguineus sensu lato were recorded for the first-time parasitizing Baird’s tapirs. We did not find a relationship between body condition, sex, and age classes of tapirs versus the number of parasitizing tick species. Our finding demonstrates that the richness of ticks parasitizing tapirs does not depend on the biological characteristics and health status of the host, but could be determined by other factors such as habitat use and the rate of contact with domestic animals.

Growth, carcass and meat quality characteristics of Charolais-sired steers and heifers born to Angus-cross-dairy and Angus breeding cows

Charolais-sired heifers and steers from Angus, Angus × Holstein-Friesian, Angus × Holstein-Friesian-Jersey and Angus × Jersey cows were measured for growth, carcass, and meat quality characteristics. Despite differences in weaning weight and growth rate, the progeny of different breed-crosses did not differ in final live weight or carcass weight (P > 0.05). Carcass and meat quality characteristics did not differ among breed-crosses (P > 0.05), except for fat that was more yellow in progeny from Angus and Angus-cross-Jersey dams. Steers were slaughtered older and had heavier carcasses with greater fat depth and intramuscular fat than heifers. Meat quality differed between the sex classes, with steers having greater pH and shear force, redder meat, and yellower fat than heifers. Angus-cross-dairy cows when crossed with a beef breed sire such as the Charolais will provide progeny for meat production which are competitive to beef breeds for beef finishing and meat production and therefore, a useful mechanism to utilize surplus animals from the dairy industry.